1. Field of the Invention
The present invention relates to a light source device and a projector.
2. Description of Related Art
Conventionally, projectors that form an optical image by modulating a light beam irradiated by a light source in accordance with image information and project the optical image in an enlarged manner are used in the field of home theaters.
The projectors have a light source device having a light source lamp (light-emitting tube), a reflector that reflects a light beam irradiated by the light source lamp and a lamp housing that houses the light source lamp and the reflector.
In recent projectors, in order to clearly display the projected optical image, it is required to increase the luminance of a light source lamp. Since the high-luminance light source lamp causes to raise the temperature inside the lamp housing, the air in the projector is introduced from the upper side of the lamp housing of the light source device to be flown to the lower side thereof to cool the inside of the lamp housing (For instance, see JP08-186784A, page 9, FIG. 7).
In the above cooling method, however, the cooling air flows only from the top to the bottom of the lamp housing, so that it is difficult to equally cool the reflector. Therefore, the reflector may be partly subjected to high temperature. Ordinary, a reflecting film that reflects visible rays and transmits infrared rays and ultraviolet rays of the light beam irradiated from the light source lamp is attached on the reflecting portion of the reflector, but the reflecting film may be peeled off because of the partial high temperature of the reflector.
As disclosed in the above publication, since the reflector and the light source lamp are traditionally housed in the lamp housing, the infrared rays and the ultraviolet rays transmitted through the reflector irradiate the wall of the lamp housing located behind the reflector. The temperature of the wall of the lamp housing then becomes high, thus being thermally deformed. Further, due to ultraviolet rays transmitted through the reflector, the lamp housing may be thermally and chemically decomposed, and accordingly, the wall surface of the lamp housing may be deteriorated and whitened. Additionally, adhesion of siloxane generated by chemical decomposition on optical components may deteriorate the performance thereof, and foul smell caused by generation of endocrine disrupters may lower the reliability.
Incidentally, the above disadvantages are occurred not only when the infrared rays and the ultraviolet rays transmitted through the reflector irradiate the wall of the lamp housing but also when they irradiate the wall of the light guide housing the optical components.